1. Field of the Invention
The present invention relates to door knob handle attachments, and more particularly pertains to a new and improved door knob handle attachment to enable disabled individuals to more easily open doors. Individuals suffering from arthritis, crippling hand deformities, loss of grasping power or missing arms are presented with an extreme obstacle in the form of the conventional round door knob. In order to overcome this problem, the present invention provides a simple attachment for conventional round door knobs which converts the door knob into a lever type door handle.
2. Description of the Prior Art
Various types of door knob handle attachments are known in the prior art. A typical example of such a door knob handle attachment is to be found in U.S. Pat. No. 3,575,453, which issued to P. Hohl on Apr. 20, 1971. This patent discloses a lever attachment for a round door knob secured by an arcuate serrated clamp. The clamp is secured around a round door knob by tightening a nut on an elongated bolt. The device is unattractive and provides no protection against the hazardous exposure of the free end of the clamping bolt. U.S. Pat. No. 4,018,465, which issued to V. Ramler on Apr. 19, 1977, discloses a lever door handle attachment which is clamped on conventional round door knobs. The device requires the existing round door knob to be drilled to receive alignment pins of the attachment. The device is thus difficult and expensive to install and cannot be removed without exposing the scarred surface of the original door knob. U.S. Pat. No. 4,223,931, which issued to R. Neary on Sept. 23, 1980, discloses a door knob handle attachment having a bifurcated end portion for insertion over the shank of a door knob. The device requires that a tapped hole be provided in the back face of the door knob, and is thus difficult and expensive to install. U.S. Pat. No. 4,397,489, which issued to W. Lind on Aug. 9, 1983, discloses an adaptor for providing a lever attachment to a round door knob. A hollow threaded cylinder has an attached lever and an interior hollow space lined with a resilient material. A threaded plug at one end of the cylinder is tightened to compress the resilient material to frictionally engage a door knob. U.S. Pat. No. 4,504,087, which issued to A. Pennington on Mar. 12, 1985, discloses a lever attachment for a rotary door knob which is formed as a split one piece unit adapted to expand to embrace a door knob. The lever is formed by two split mating portions which are secured together around the door knob by a variety of latch mechanisms. This device is unsightly because of the split construction which can also leave uncomfortable exposed edges. Additionally, the latch construction fails to securely clamp the mounting collar around the door knob, thus resulting in an insecure attachment.
While the above mentioned devices are suited for their intended usage, none of these devices disclose an inexpensive lever attachment which utilizes two mating semi-circular shell members provided with undercut recesses to completely surround and firmly engage a round door knob. Additionally, none of the aforesaid devices disclose the use of mating semi-circular shell members provided with integrally formed hinge portions and each having an arcuate undercut recess lined with a resilient material for frictional engagement with a conventional round door knob. An additional feature of the present invention, not contemplated by the aforesaid prior art devices, is the provisions of radially movable concave clamp members for allowing adaptation to round door knobs of varying size. Inasmuch as the art is relatively crowded with respect to these various types of door knob handle attachments, it can be appreciated that there is a continuing need for and interest in improvements to such door knob handle attachments, and in this respect, the present invention addresses this need and interest.